Fusionfire - 16-5-2012 at 02:47
Hi guys,
Just out of curiosity can anyone find some solvation reactions with lower heats of solvation (on a per gram basis) than some of the following below?
Ammonium nitrate
Molecular mass = 80.05 g/mol
Heat of solvation = 25.69 kJ/mol
Specific heat of solvation = 0.32 kJ/g
Urea
Molecular mass = 60.06 g/mol
Heat of solvation = 13.8 kJ/mol
Specific heat of solvation = 0.23 kJ/g
Potassium chlorate
Molecular mass = 122.55 g/mol
Heat of solvation = 41.38 kJ/mol
Specific heat of solvation = 0.34 kJ/g
I am looking for something that is also reversible by heating to drive the water off so you can "recharge" the system (i.e. the recharge temperature
is not above the decomposition temperature!)
Thanks.
White Yeti - 16-5-2012 at 18:39
One simple endothermic reaction you might be interested in:
CaCl2 + 2NaHCO3 ----> CaCO3 +2NaCl + CO2 +H2O +72.4 kJ/mol
The solvation of CaCl2 as everyone knows is exothermic, so you have to dissolve the CaCl2 first, let it cool and then add the bicarbonate ¡slowly!
Fusionfire - 16-5-2012 at 22:26
Interesting, I didn't know about that reaction. You learn new things every day 
CaCl2 (anhydrous) 110.98 g/mol
NaHCO3 84.007 g/mol
Heat of reaction 72.4 kJ/mol
Specific heat of reaction = 0.26 kJ/g